The present invention relates to a lubrication control apparatus for a start clutch disposed between an automatic transmission and a power source.
Generally, an automatic transmission is connected to an engine through a torque converter. Such a torque converter enables a smooth power transmission although its slipping degrades a fuel consumption efficiency. In order to further improve a power transmitting efficiency, there is proposed a power transmission system employing an electromagnetic clutch or hydraulic clutch instead of a torque converter.
Each of Japanese Patent Provisional Publications Nos. 10-331869 and 5-149418 discloses such a power transmission system which employs a hydraulic clutch as a start clutch. In view of a structural simplicity and a performance of a system, an electromagnetic clutch is preferable to a hydraulic clutch.
However, even if an electromagnetic clutch is employed as a start clutch instead of a torque converter, it is necessary to lubricate the electromagnetic start clutch when the start clutch is put in a slipping state. Further, it is preferable to accurately execute the lubrication of the start clutch according to the slipping state of the start clutch and to adapt a torque-converter type automatic transmission to automatic transmission employing an electromagnetic type start clutch without largely changing the design of the automatic transmission for providing a start clutch lubrication apparatus.
It is therefore an object of the present invention to provide a start clutch lubrication apparatus of an automatic transmission which is arranged to solve the above-mentioned problems.
An aspect of the present invention resides in a lubrication control apparatus for a start clutch of an electromagnetic type. The start clutch is disposed between a power source and an automatic transmission to transmit the power of the power source to the automatic transmission. The start clutch lubrication apparatus comprises oil supplying means for supplying lubricating oil to the start clutch, oil returning means for returning the lubricating oil from the start clutch to the automatic transmission, and quantity varying means for varying a supply quantity of the lubricating oil supplied to the start clutch according to a slipping state of the start clutch.
Another aspect of the present invention resides in a lubrication control apparatus for an electromagnetic start clutch disposed between an engine and an automatic transmission. The lubrication control apparatus comprises a start clutch operating condition detector that obtains information indicative of an operating condition of the start clutch, an oil-quantity varying valve-unit that varies a supply quantity of lubricating oil supplied to the start clutch and a controller coupled to the start clutch operating condition detector and the lubricating oil quantity varying valve unit. The controller is arranged to determine the operation condition of the start clutch on the basis of the information obtained by the start clutch operating condition detector, to determine a supply quantity of the lubricating oil supplied to the start clutch according to the operating condition of the start clutch, and to output a control signal to the oil-quantity varying valve-unit to control the supply quantity to the start clutch at the determined supply quantity.
Further another aspect of the present invention resides in a method for controlling a lubricating oil quantity supplied to a start clutch of an electromagnetic type. The start clutch is disposed between an engine and an automatic transmission, the method comprises a step of obtaining information indicative of an operating condition of the start clutch, a step of determining an operation condition of the start clutch on the basis of the information indicative of the operating condition of the start clutch, a step of determining a supply quantity of the lubricating oil supplied to the start clutch according to the operating condition of the electromagnetic clutch, and a step of controlling the lubricating oil quantity supplied to the start clutch at the determined supply quantity.